The invention relates to nonlinear Fabry-Perot etalons, and more specifially to use of etalons as logic elements.
Use of nonlinear Fabry-Perot cavities or etalons is known. Typically, an etalon is biased by means of a bias beam having a wavelength which is nearly an integral multiple of the optical thickness of the etalon. However, prior optical switches absorb a lot of light energy, due to the fact that the bias beam is partially absorbed to modify the index of refraction to hold the switch in an on state, and also due to the fact that the switch is an on state, and also due to the fact that the switch is held in its on state for an entire cycle. This results in heating of the device, which can cause the switch to work improperly. Much research on optical bi-stable devices has been published, for example, in "Optical Modualtion by Optical Tuning of a Cavity" by H. M. Gibbs et al., Applied Physics Letters, Volume 34, No. 8, Apr. 15, 1979, page 511, "Optical Bi-Stable Devices: The Basic Components of All-Optical Systems?" by H. H. Gibbs et al., Optical Engineering, Volume 19, No. 4, July/August 1980, page 463, and "Switching of a GaAs Bi-Stable Etalon: External Switching On and Off, Regenerative Pulsations, Transverse Effects, and Lasing", by H. M. Gibbs et al. Other optical logic elements have also been demonstrated as in "Optical Logic Gates Using a Hughes Liquid Crystal Light Valve" by S. A. Collins, Jr., et al., SPIE, Volume 232, 1980 International Optical Computing Conference, page 168, and see C. P. Seaton et al., Applied Physics Letters, Volume 42, No. 2, Jan. 15, 1983, page 131. See also "Physics of Optical Switching", by R. L. Fork, Physical Review A, Volume 26, No. 4, October 1982, page 2049. However, none of the prior optical logic gates has the capability of driving numerous successive similar logic elements, due to attenuation of light intensity or lack of a convenient means of regeneration of light signal strength.
Therefore, it is a primary object of the invention to provide an improved optical logic element which is simple to operate, capable of reliably performing logical operations using a single Fabry-Perot etalon at substantially higher speed, and with lower power dissipation than any prior high speed optical logic elements.
It is another object of the invention to provide an optical logic element which is capable of producing output beams representing logic combinations of light encoded logic signals with sufficient intensity to drive subsequent optical logic element stages without use of any gain medium.
It is another object of the invention to provide an optical logic element which is capable of producing output beams representing logic combinations of light encoded logic signals with reduced intensity and yet having the capability of driving subsequent optical logic element stages without the use of any gain medium.
It is another object of the invention to provide an optical logical element apparatus and method for simultaneous multiple optical logic operations in successive stages at very low power dissipation and high data rates.
It is another object of the invention to provide an optical logic element producing high speed, low power inverting logic functions with high contrast output beams.